Supporters say the CBD Metro is a brave new underground world. Cynics call it a fast train to nowhere. Robert Milliken explores an idea whose time has come.

Clover Moore, Sydney's Lord Mayor, reckons the city's most critical problem is a transport system it has long outgrown. She sees the threat to Sydney's regional standing as a global city coming not from Melbourne or Brisbane but from Singapore or Shanghai, both of which are "pouring billions into new transport".Read more